drop table if exists t1, t2, t3; create table t1 (kill_id int); insert into t1 values(connection_id()); select ((@id := kill_id) - kill_id) from t1; ((@id := kill_id) - kill_id) 0 kill @id; select ((@id := kill_id) - kill_id) from t1; ((@id := kill_id) - kill_id) 0 select @id != connection_id(); @id != connection_id() 1 select 4; 4 4 drop table t1; kill (select count(*) from mysql.user); ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select count(*) from mysql.user)' at line 1 create table t1 (id int primary key); create table t2 (id int unsigned not null); insert into t2 select id from t1; create table t3 (kill_id int); insert into t3 values(connection_id()); select id from t1 where id in (select distinct a.id from t2 a, t2 b, t2 c, t2 d group by a.id, b.id, c.id, d.id having a.id between 10 and 20); select ((@id := kill_id) - kill_id) from t3; ((@id := kill_id) - kill_id) 0 kill @id; Got one of the listed errors drop table t1, t2, t3; select get_lock("a", 10); get_lock("a", 10) 1 select get_lock("a", 10); get_lock("a", 10) NULL select 1; 1 1 select RELEASE_LOCK("a"); RELEASE_LOCK("a") 1 create table t1(f1 int); create function bug27563() returns int(11) deterministic begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; set @a= get_lock("lock27563", 10); return 1; end| select get_lock("lock27563",10); get_lock("lock27563",10) 1 insert into t1 values (bug27563()); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 insert into t1 values(0); update t1 set f1= bug27563(); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 insert into t1 values(1); delete from t1 where bug27563() is null; ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 1 select * from t1 where f1= bug27563(); ERROR 70100: Query execution was interrupted select @a; @a NULL create procedure proc27563() begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; select get_lock("lock27563",10); select "shouldn't be selected"; end| call proc27563(); get_lock("lock27563",10) NULL ERROR 70100: Query execution was interrupted select @a; @a NULL create table t2 (f2 int); create trigger trg27563 before insert on t1 for each row begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; set @a:= get_lock("lock27563",10); insert into t2 values(1); end| insert into t1 values(2),(3); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 1 select * from t2; f2 select release_lock("lock27563"); release_lock("lock27563") 1 drop table t1, t2; drop function bug27563; drop procedure proc27563; PREPARE stmt FROM 'EXPLAIN SELECT * FROM t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,t11,t12,t13,t14,t15,t16,t17,t18,t19,t20,t21,t22,t23,t24,t25,t26,t27,t28,t29,t30,t31,t32,t33,t34,t35,t36,t37,t38,t39,t40 WHERE a1=a2 AND a2=a3 AND a3=a4 AND a4=a5 AND a5=a6 AND a6=a7 AND a7=a8 AND a8=a9 AND a9=a10 AND a10=a11 AND a11=a12 AND a12=a13 AND a13=a14 AND a14=a15 AND a15=a16 AND a16=a17 AND a17=a18 AND a18=a19 AND a19=a20 AND a20=a21 AND a21=a22 AND a22=a23 AND a23=a24 AND a24=a25 AND a25=a26 AND a26=a27 AND a27=a28 AND a28=a29 AND a29=a30 AND a30=a31 AND a31=a32 AND a32=a33 AND a33=a34 AND a34=a35 AND a35=a36 AND a36=a37 AND a37=a38 AND a38=a39 AND a39=a40 '; EXECUTE stmt;